chore: update project structure with contracts and services for CaddyManager, including configuration and Docker integration

CaddyManager.Contracts/Docker/IDockerService.cs

@@ -0,0 +1,13 @@
+namespace CaddyManager.Contracts.Docker;
+
+/// <summary>
+/// Contract for the service to interact with Docker
+/// </summary>
+public interface IDockerService
+{
+    /// <summary>
+    /// Method to help restart the Caddy container
+    /// </summary>
+    /// <returns></returns>
+    Task RestartCaddyContainerAsync();
+}